Bureau of Mines / Minerals yearbook: Metals, minerals, and fuels 1972
Year 1972, Volume 1 (1972)
Mica, pp. 783-791 ff. PDF (752.3 KB)
MICA 791 Crude mica production, based on exports plus consumption, increased slightly from 35,119 tons in 1971 to 37,299 tons in 1972. Exports also increased from 26,319 tons valued at $21.7 million in 1971 to 27,949 tons valued at $25.3 million in l972. Thirty-two percent of exports in both 1971 and 1972 consisted of sheet mica. The remainder consisted of other forms of processed and scrap mica. TECHNOLOGY The work of the Bureau of Mines in the area of recovery of mica concentrates by flotation from weathered mica pegmatites and micaceous schist ores has been reviewed. The acid cationic and alkaline anionic-cationic method for the recovery of coarse and fine mica, respectively, are discussed and flowsheets -for their use were provided. In addition, mining, recovery, and grinding of mica were discussed.2 Batch laboratory scale tests were run on several industrial minerals -that included mica to determine the optimum grinding constants. The test used an attrition grinding process developed previously by the Bureau of Mines.3 A method has been developed -to break apart natural, synthetic, or mixtures of mica by initially heating the material to drive off the water of hydration. The heated -material is then broken apart in oi-iented streams of an inert gas such as argon to produce thin, smooth-surfaced particles, or flakes with a high specific surface area and a high ratio of length to thickness.4 2Browning, James S. Mica Beneficiation. EuMines Bull. 662, 1973, 21 pp. ' Stanczyk, Martin H., and I. L. Feld. Ultrafine Grinding of Several Industrial Minerals by the Attrition Grinding Process. BuMines RI 7641., 1972, 25 pp. 4 Ruzikk, 3. Ultradisintegration of Natural or Synthetic Mica. U.S. Pat. 3,719,329, Mar. 6, 1973.
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